Page 124 of 139 FirstFirst ... 2474114122123124125126134 ... LastLast
Results 1,231 to 1,240 of 1381

Thread: Cuda's Cars, v2.0

  1. #1231
    Senior Member
    Join Date
    Jan 2014
    Posts
    6,265
    Aluminum is likely from piston wear, not bearings. Bearings are usually brass when they start to show up.

    Iron is either from the cylinder liner, or the rings themselves. Usually the first thing to go on a tired engine.

    What were your compression test numbers again?

  2. #1232
    Oh I forgot to post those here.

    There are different opinions ranging from "do 4 cranks" to "crank until the reading stabilizes". At 4 cranks my numbers would have all been pretty low, so I did 8 cranks, paused to get the reading, and then cranked until it stabilized. The first number is 8 cranks, second number is stabilized reading:

    #1: 175, 205
    #2: 165, 180
    #3: 170, 190
    #4: 180, [not performed, I actually went in reverse order and didn't think to take a stabilized reading until after this cylinder]

    Looks like solid numbers except for the 15psi difference between cylinders. #2 looking a little low.

    Back to the noise that prompted all this investigation, it doesn't seem to be totally consistent with either piston slap or rod knock, but does sound wrong enough to look into. I'm pretty curious what I will find eventually.

    I haven't been able to find a lot of detail on what metals are used in the 1ZZ-FE, but I did find that it uses thin cast iron liners in the aluminum block. It was pointed out to me in another forum that a sloppy timing chain/tensioner could hit the timing cover, which is aluminum also.

    -

    Unfortunately no mycelial network spore drive on this slow thing.

  3. #1233
    反重力 Rikadyn's Avatar
    Join Date
    Jan 2014
    Posts
    1,713
    Reminds me that I should check my tensioner in the spring...does it sound like a KA? ��

  4. #1234
    Senior Member
    Join Date
    Jan 2014
    Posts
    6,265
    Yeah... So cylinder number 2 is at what most would call "out of range". The reading is substantially out of range, enough so, that I would perform a leak down test.

  5. #1235
    Because of the 15psi difference from the highest cylinder? That does seem borderline. The absolute numbers themselves are well within spec according to my info (184psi is spec, 145psi is minimum).

    I did get a better scope with a side camera built into it, which is much more appropriate for examining cylinder walls. Pics and short videos: https://photos.app.goo.gl/X64Vpvgn7YdEERBn8 (pistons on the left, head on the right)

    I wish I could know if these crosshatch marks are too deep or are fine. Lots of them have irregular shapes and trajectories in my uneducated opinion. It makes me wonder if an amateur mechanic did a sloppy hone job with a cheap tool in the not too distant past.

    Also,
    - Typically the areas that have cross hatches worn away are where the 'taller' parts of the pistons are. Side force wear I'd guess, from the forces the crank/rods exert on the pistons. The straight grooves in these areas and lack of crosshatch make me wonder how oval the cylinders might be.
    - Two of the cylinders have what looks like a couple of pits. One cylinder has what appears to be rust in the pits.

    This is my first time really seeing the inside of a well used engine. The cylinders look not-so-good to me, but we are looking at it pretty up close and I can't feel how deep anything is. If the things that look like pits are in fact pits, the rust has to mean it's not through the iron liner, because aluminum wouldn't turn that color when it corrodes, right?

    -

    In MR2 Turbo news, I borrowed a paint depth gauge and took some readings around the car. Looks like there's plenty of clearcoat left which is a great sign for a car about to turn 30.

  6. #1236
    Senior Member
    Join Date
    Jan 2014
    Posts
    1,484
    Quote Originally Posted by CudaMan View Post
    Looks like there's plenty of clearcoat left which is a great sign for a car about to turn 30.
    The last part of that makes me feel very old.
    -Formerly Stabulator

  7. #1237
    反重力 Rikadyn's Avatar
    Join Date
    Jan 2014
    Posts
    1,713
    I'd expect more uniformity even from a cheap home hone (Dingle ball is only like 50 bucks).

  8. #1238
    Senior Member
    Join Date
    Jan 2014
    Posts
    6,265
    Usually from highest to lowest reading if greater than 10% difference is considered a fail. Hope that clears this up.

    As for the cross hatching, something is definitely going on. The vertical markings are highly suspect of failed rings, or something along those lines. I also noticed several areas of pitting, as you mentioned.

    The horizontal darkened areas are exactly as you mention, that's where the rings and pistons are the top of the stroke. On high mileage and high wear engines, there will be a discernable lip there.

    I also notice a lot of carbon build up. How many miles on this engine again?

  9. #1239
    Somewhere around 140-150k as I recall, putting the puzzle pieces together from the CarFax reports of the Spyder and the Celica that this engine came out of.

    Toyota specifies 15psi maximum difference in cylinder compression for this engine, so according to that spec this one is right on the border. I don't mind putting a new hone and rings in it, my comfort/knowledge level isn't at the point where I know whether the engine needs to be bored out or not. I *think* if it did need an overbore that would mean new larger pistons are needed, or I wonder if just larger rings can make up the difference for a small enough overbore. I'm guessing to be accurate a machine shop would have to measure the cylinder wall bores to get an idea of the absolute value, because the largest I've heard of working on this engine is a .5mm overbore and I'd bet with enough wear it could be some way towards that in places as it sits now. But like I say I'm a bit out of my depth at the moment. I was hoping the cylinder bore inspection would give me a clear indication to either A) just throw new rings/hone at it, or B) toss the block in the bin.

    One thing I should do when I have time and sunny weather is to inspect a cylinder or two in the other cars just to see what "normal" might look like in a similar era higher mileage engine (130k on the BMW) and an old school engine with ~70k miles on a rebuild (the MR2 Turbo). Or maybe it was a new Toyota long block... been too long since I looked thru the receipts!

    Side note, just listen to how good this engine can sound when healthy with a racy exhaust!


    @Russ, any news on your Spyder?

  10. #1240
    Quote Originally Posted by JoshInKC View Post
    The last part of that makes me feel very old.
    I've had a couple people ask me if I was the original owner of the '93 Turbo. Moreso when I was younger actually. I did feel old, even though I was 11 when this car was built. I suppose some 16 year olds can buy a nice sports car as their first car, but still.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •